Bug 1003968 - avoid Exists() calls for search plugin directories in the browser directory provider r=daleharvey,Gijs

This Change removes all call to Exists() in Directory Provider component, which creates the possibility for the componenet to return an empty list. SearchService.jsm is modified to handle this possibility.

Differential Revision: https://phabricator.services.mozilla.com/D42772

--HG--
extra : moz-landing-system : lando

browser/base/content/test/performance/browser_startup_mainthreadio.js

@@ -554,13 +554,6 @@ const startupPhases = {
       stat: 1,
       close: 1,
     },
-    {
-      // bug 1003968
-      path: "XREAppDist:searchplugins",
-      condition: WIN,
-      ignoreIfUnused: true, // with WebRender enabled this may happen during "before becoming idle"
-      stat: 1,
-    },
     {
       path: "XCurProcD:extensions",
       condition: WIN,
@@ -665,13 +658,6 @@ const startupPhases = {
       ignoreIfUnused: true,
       stat: 3,
     },
-    {
-      // bug 1003968
-      path: "XREAppDist:searchplugins",
-      condition: WIN,
-      ignoreIfUnused: true, // with WebRender enabled this may happen during "before handling user events"
-      stat: 1,
-    },
   ],
 };
 

browser/components/dirprovider/DirectoryProvider.cpp

@@ -64,16 +64,11 @@ static void AppendDistroSearchDirs(nsIProperties* aDirSvc,
   if (NS_FAILED(rv)) return;
   searchPlugins->AppendNative(NS_LITERAL_CSTRING("searchplugins"));
 
-  bool exists;
-  rv = searchPlugins->Exists(&exists);
-  if (NS_FAILED(rv) || !exists) return;
-
   nsCOMPtr<nsIFile> commonPlugins;
   rv = searchPlugins->Clone(getter_AddRefs(commonPlugins));
   if (NS_SUCCEEDED(rv)) {
     commonPlugins->AppendNative(NS_LITERAL_CSTRING("common"));
-    rv = commonPlugins->Exists(&exists);
-    if (NS_SUCCEEDED(rv) && exists) array.AppendObject(commonPlugins);
+    array.AppendObject(commonPlugins);
   }
 
   nsCOMPtr<nsIPrefBranch> prefs(do_GetService(NS_PREFSERVICE_CONTRACTID));
@@ -92,11 +87,8 @@ static void AppendDistroSearchDirs(nsIProperties* aDirSvc,
       rv = localePlugins->Clone(getter_AddRefs(defLocalePlugins));
       if (NS_SUCCEEDED(rv)) {
         defLocalePlugins->AppendNative(defLocale);
-        rv = defLocalePlugins->Exists(&exists);
-        if (NS_SUCCEEDED(rv) && exists) {
-          array.AppendObject(defLocalePlugins);
-          return;  // all done
-        }
+        array.AppendObject(defLocalePlugins);
+        return;  // all done
       }
     }
 
@@ -108,11 +100,8 @@ static void AppendDistroSearchDirs(nsIProperties* aDirSvc,
     rv = localePlugins->Clone(getter_AddRefs(curLocalePlugins));
     if (NS_SUCCEEDED(rv)) {
       curLocalePlugins->AppendNative(locale);
-      rv = curLocalePlugins->Exists(&exists);
-      if (NS_SUCCEEDED(rv) && exists) {
-        array.AppendObject(curLocalePlugins);
-        return;  // all done
-      }
+      array.AppendObject(curLocalePlugins);
+      return;  // all done
     }
   }
 }
@@ -145,8 +134,6 @@ DirectoryProvider::AppendingEnumerator::GetNext(nsISupports** aResult) {
 
   mNext = nullptr;
 
-  nsresult rv;
-
   // Ignore all errors
 
   bool more;
@@ -166,10 +153,6 @@ DirectoryProvider::AppendingEnumerator::GetNext(nsISupports** aResult) {
       ++i;
     }
 
-    bool exists;
-    rv = mNext->Exists(&exists);
-    if (NS_SUCCEEDED(rv) && exists) break;
-
     mNext = nullptr;
   }
 

toolkit/components/search/SearchService.jsm

@@ -1062,6 +1062,10 @@ SearchService.prototype = {
         if (!done) {
           distDirs.push(dir);
         }
+      } catch (ex) {
+        if (!(ex instanceof OS.File.Error) || !ex.becauseNoSuchFile) {
+          throw ex;
+        }
       } finally {
         iterator.close();
       }